Error in installing Frappe

I am using Ubuntu 16.04. While installing, I am getting the following problem.

Installing for Ubuntu xenial amd64
In case you encounter an error, you can post on https://discuss.frappe.io

Adding ubuntu mariadb repo
Installing packages for Ubuntu. This might take time…
Reading package lists…
Building dependency tree…
Reading state information…
build-essential is already the newest version (12.1ubuntu2).
build-essential set to manually installed.
fontconfig is already the newest version (2.11.94-0ubuntu1).
fontconfig set to manually installed.
libxext6 is already the newest version (2:1.3.3-1).
libxext6 set to manually installed.
libxrender1 is already the newest version (1:0.9.9-0ubuntu1).
libxrender1 set to manually installed.
libxslt1.1 is already the newest version (1.1.28-2.1).
libxslt1.1 set to manually installed.
xfonts-base is already the newest version (1:1.0.4+nmu1).
xfonts-base set to manually installed.
The following additional packages will be installed:
git-man icu-devtools libaio1 libcrypto++9v5 libdbd-mysql-perl libdbi-perl
liberror-perl libexpat1 libexpat1-dev libhtml-template-perl libicu-dev
libjemalloc1 libmariadbclient18 libmysqlclient18 libmysqlclient20 libopts25
libpython-all-dev libpython-dev libpython2.7-dev libreadline5 libssl-doc
libssl1.0.0 libuv1 libxml2 libxml2-dev mariadb-client-10.0
mariadb-client-core-10.0 mariadb-server-10.0 mariadb-server-core-10.0
mysql-common nginx-common nginx-core python-all python-all-dev python-meld3
python-pip-whl python-pkg-resources python-wheel python2.7-dev redis-tools
vim-runtime zlib1g-dev
Suggested packages:
git-daemon-run | git-daemon-sysvinit git-doc git-el git-email git-gui gitk
gitweb git-arch git-cvs git-mediawiki git-svn libmldbm-perl
libnet-daemon-perl libsql-statement-perl libipc-sharedcache-perl icu-doc
libterm-readkey-perl mailx mariadb-test tinyca fcgiwrap nginx-doc ntp-doc
procmail postfix-mysql postfix-pgsql postfix-ldap postfix-pcre sasl2-bin
dovecot-common postfix-cdb postfix-doc python-egenix-mxdatetime
python-mysqldb-dbg python-setuptools-doc ruby-redis iselect | screenie
| byobu ncurses-term supervisor-doc ctags vim-doc vim-scripts vim-gnome-py2
| vim-gtk-py2 | vim-gtk3-py2 | vim-athena-py2 | vim-nox-py2
The following NEW packages will be installed:
git git-man htop icu-devtools libaio1 libcrypto+±dev libcrypto++9v5
libdbd-mysql-perl libdbi-perl liberror-perl libexpat1-dev
libhtml-template-perl libicu-dev libjemalloc1 libmariadbclient-dev
libmariadbclient18 libmysqlclient18 libmysqlclient20 libopts25
libpython-all-dev libpython-dev libpython2.7-dev libreadline5 libssl-dev
libssl-doc libuv1 libxml2-dev libxslt1-dev mariadb-client-10.0
mariadb-client-core-10.0 mariadb-common mariadb-server mariadb-server-10.0
mariadb-server-core-10.0 mysql-common nginx nginx-common nginx-core nodejs
ntp postfix python-all python-all-dev python-dev python-meld3 python-mysqldb
python-pip python-pip-whl python-pkg-resources python-setuptools
python-wheel python2.7-dev redis-server redis-tools screen supervisor vim
vim-runtime xfonts-75dpi zlib1g-dev
The following packages will be upgraded:
libexpat1 libssl1.0.0 libxml2
3 upgraded, 60 newly installed, 0 to remove and 249 not upgraded.
Need to get 82.9 MB of archives.
After this operation, 357 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
mysql-common mariadb-common libmysqlclient18 libmariadbclient18
mariadb-client-core-10.0 mariadb-client-10.0 mariadb-server-core-10.0
mariadb-server-10.0 libmariadbclient-dev mariadb-server
E: There were unauthenticated packages and -y was used without --allow-unauthenticated

So, can I install those three separately using -
ned on the repository of the package, so I manually installed the packages:

apt-get install mariadb-server
apt-get install mariadb-client
apt-get install libmariadbclient-dev

You should use the beta script:, it supports 16.04

wget https://raw.githubusercontent.com/frappe/bench/develop/playbooks/install.py
python install.py --develop